/*

 * Licensed to the Apache Software Foundation (ASF) under one

 * or more contributor license agreements.  See the NOTICE file

 * distributed with this work for additional information

 * regarding copyright ownership.  The ASF licenses this file

 * to you under the Apache License, Version 2.0 (the

 * "License"); you may not use this file except in compliance

 * with the License.  You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package com.bff.gaia.unified.runners.gaia.translation.wrappers.streaming;



import java.util.stream.Stream;



/**

 * Helper that keeps pushed-back data, most likely due to side inputs that are not available.

 *

 * <p>Implementations of this must use Gaia state to make sure pushed-back data is fault tolerant.

 *

 * @param <T> The type of pushed back elements.

 */

interface PushedBackElementsHandler<T> {



  /** Returns all pushed back elements. */

  Stream<T> getElements() throws Exception;



  /** Clears the pushed back elements. */

  void clear() throws Exception;



  /** Adds the given element to the pushed back elements. */

  void pushBack(T element) throws Exception;



  /** Adds all the given element to the pushed back elements. */

  void pushBackAll(Iterable<T> elements) throws Exception;

}